1. Field of the Invention
The present invention relates to a power supply device having improved power conversion efficiency in light load condition.
2. Description of the Related Art
Recently, various types of electronic devices, such as computers, display devices, various control devices, and the like that meet various requirements have been used domestically, commercially and industrially.
These electronic devices have essentially adopted a power supply device supplying required driving power so as to perform various operations while meeting various requirements.
Meanwhile, in order to meet the requirements of high power specifications, in the foregoing power supply device, a full bridge converter capable of reducing a switching loss by implementing zero voltage switching using a phase shift control has been prevalently used.
The foregoing full bridge converter may include two leading leg switches and two lagging leg switches, similarly to the invention disclosed in the following related art document.
However, in case of the leading leg switch, the zero voltage switching can be made in the overall load region, but in case of the lagging leg switch, as the load is decreased, the zero voltage switching may not be smoothly performed, and thus, the power conversion efficiency may be drastically degraded in a light load region.